Photochromic transitions of copolymers of indolinospiropyran

Abstract The spectral, kinetic and photochemical properties of solutions of copolymers of indolinospiropyran with various vinyl comonomers have been studied. It is shown that increase in the polarity of the solvent, in the size of the side group of the comonomer and in the concentration of the photochronic component of the polymer cause a hypsochromic shift of the absorption band of the coloured form of the copolymer, and decrease in the rate constant of decolourization in the dark and in the quantum yields of photochemical colouration, decolourization and decomposition. This behaviour of the copolymers is explained by the polar and steric effect of the polymer chain on the photochromic properties of the spiropyran.